In a Multiple Regression Model, Which of the Following Is

In a multiple regression model, which of the following is true?

A) The coefficient of determination will be equal to the square of the highest correlation in the correlation matrix.
B) Adding variables that have a low correlation with the dependent variable will cause the R-square value to decline.
C) The sum of the residuals computed for the least squares regression equation will be zero.
D) The adjusted R-square might be higher or lower than the value of the R-square.